Tetrahydropyrimidine compound photographic products and processes having a polycyclic s substituted

ABSTRACT

THE PRESENT INVENTION IS DIRECTED TO THE USE OF CERTAIN POLYCYCLIC, S-SUBSTITUTED TETRAHYDROPYRIMIDINE COMPOUNDS AS TONING AGENTS FOR SILVER IMAGES.

United States Patent 01 Efice 3,756,825 Patented Sept. 4, 1973 3,756,825 PHOTOGRAPHIC PRODUCTS AND PROCESSES HAVING A POLYCYCLIC S-SUBSTITUTED TET- RAHYDROPYRIMIDINE COMPOUND Donald 0. Rickter, Arlington, Mass., assignor to Polaroid Corporation, Cambridge, Mass. No Drawing. Filed Feb. 25, 1972, Ser. No. 229,504 Int. Cl. G03c 1/48 US. C]. 96-76 R 18 Claims ABSTRACT OF THE DISCLOSURE The present invention is directed to the use of certain polycyclic, S-substituted tetrahydropyrimidine compounds as toning agents for silver images.

BACKGROUND OF THE INVENTION The present invention is directed to photographic processes for producing silver images possessing a black or bluish-black image tone, and particularly to materials providing such tone.

It is well known in processes for forming photographic silver images that the silver image is not black, but rather brown or some other unacceptable color. This is particularly true in silver halide diffusion transfer processes.

'In a typical silver diffusion transfer process, a lightsensitive silver halide material is given an imagewise exposure and, in the presence of a developing agent, a silver halide complexing liquid and a processing liquid brought into contact with an image-receiving layer. The exposed silver halide grains are developed and do not undergo any further change. The unexposed silver halide grains are complexed and transferred by diffusion into the receiving element where it is converted into a silvercontaining image under the action of the developing nuclei. Thus, a positive image of the original appears in the receiving layer after separation of the image-receiving material from the silver halide material.

However, a disadvantage of the silver salt diffusion transfer process, particularly when metal sulfide nuclei are used, is a brown image tone of the positive image silver.

The addition of a black toning agent is generally employed to counteract the aforementioned brownish or other undesirable color of the image. However, such compounds may not be entirely eifective and may also interfere with the photographic process.

A novel class of toning agents has now been found which is not susceptible to the deficiencies of the prior art.

SUMMARY OF THE INVENTION It has now been found that silver images of good tone, i.e., blue-black images of enhanced densities, can be achieved by contacting a silver image with a compound of the formula:

wherein Z is a fused alicyclic or heterocyclic ring system containing from 3 to atoms (when the atoms common to both the ring system and the pyrimidyl group are included in the count), and more particularly, containing atoms selected from the group consisting of C, N, S and O; sa1 d ring system being disposed with respect to the pyrimldyl group in a 4,6; 4,5; 5,6; 1,6; or 4,5,6 relationship; and R is hydrogen or an atom which is a part of the ring system Z.

DETAILED DESCRIPTION OF THE INVENTION The present invention is concerned with silver images, particularly silver images which have been formed by contact with a polycyclic, S-substituted tetrahydropyrimidine toner.

The ring systems generally depicted as Z in Formula A may be either monocyclic or polycyclic. The positioning of this ring system relative to the hydropyrimidyl group is not critical for the successful practice of this invention and therefore the ring or rings which constitute said system may have various alternative sites of attachment to the main hydropyrimidyl group as indicated above. This position relationship between the above-mentioned ring system and the hydropyrimidyl group may also be described as ortho-fused, orthoand para-fused or bridged. (See Handbook of Chemistry and Physics, 52 Ed., The Chemical Rubber Company, Cleveland, Ohio.)

As examples of compounds within the scope of the present invention, mention may be made of the following:

Ell-IL and Preferably, Z comprises ring systems containing 3-10 r ng member atoms, and more preferably Z comprises lll'lgS containing 5 to 6 member atoms. The preferred group consisting of C, N, S and O atoms, and the most preferred atoms are C and N.

Formula 1 illustrates a compound which exists as both the cis-and trans-isomer. Thus, the compound of Formula 1 may be employed in the present invention as the cis-isomer, the trans-isomer or as a mixture of both. All three forms have been found to function satisfactorily as a toner.

In a preferred embodiment of the present invention, Z is selected from the group consisting of imidazo, cyclopentyl and cyclohexyl groups. Particularly preferable results have been obtained when Z is a fused 4,5 cyclopentyl group.

R, as defined above, may be hydrogen or an atom which is a part of the ring system depicted as Z. When R is so defined, a ring which is included in Z may also have, as a constituent atom, one of the nitrogens of the hydropyrimidyl group.

The toning agents of the present invention and their preparation are disclosed and claimed in copending application Ser. No. 214,665, filed Jan. 3, 1972.

The toning agents of the present invention may be disposed in the processing composition, the photosensitive emulsion, the image-receiving element or a combination of the aforementioned locations. The specific location is optional with the operator and depends on the speed with which it is desired that the toner contact the silver image. Thus, if a given toner is relatively insoluble, it may be desirable to dispose the toner in the image-receiving element.

It has been unexpectedly found that, in many cases, considerably less toner is required to achieve the desired image tone than is required with prior art materials.

The image-receiving material which can be used in a silver salt diffusion transfer process according to this invention, mostly consists of a support, e.g., of paper which carries one or more layers, one of which is the imagereceiving layer or nuclei-containing layer wherein the diffusion transfer image is formed in the presence of developing nuclei (physical and/or chemical) and/or of substances which are capable of forming developing nuclei with the diffusing complexed silver halide. The imagereceiving material can also consist of a mere paper support incorporating constituents such as developing nuclei.

The image-receiving layer may also be applied to the same support as the silver halide emulsion layer. In that case, the image-receiving layer is coated onto a support, e.g., of paper and covered with a non-hardened or slightly hardened light-sensitive silver halide emulsion layer. After exposure, development and diffusion transfer of the unexposed complexed silver halide into the image-receiving layer, the exposed and developed unhardened emulsion layer can be removed, e.g., by washing away with Warm water or by stripping after having been in contact with a sheet of common paper. Between the image-receiving layer and the light-sensitive layer there can also be present a separating layer. In a particularly preferred embodiment, the image-receiving elmeent comprises a transparent sheet having disposed thereon or incorporated therein silver precipitating nuclei. Thus, subsequent to the formation of the positive image, the silver halide emulsion layer can be removed, the image-receiving element employed as a positive transparency, suitable for viewing by projection.

The light-sensitive material suitable for a diffusion transfer process wherein black toning agents described above can be used, may be any light-sensitive silver halide material, the exposed silver halide of which is sufficiently rapidly developed and the non-exposed silver halide is sufficiently rapidly complexed to allow the formation of a diffusion transfer image to take place. Preferably, silver bromoiodochloride emulsions are used to whichsome ingredients may be added in order to obtain the desired emulsion characteristics.

The developing substance(s) can be incorporated into the light-sensitive material and/or into the bath and/or into the image-receiving material. Suitable developing substances are among others: hydroquinone, monomethyl-paminophenol sulphate, aminophenol and 3-pyrazolidinone developing substances. These developing substances can occasionally, at least partly be present in the materials used. Also combinations of two or more developing agents can be used successfully, such as the combination of hydroquinone and a 3-pyrazolidinone derivative together in the image-receiving material.

The complexing agent or silver solvent forming a soluble complex with the silver halides is preferably an alkali thiosulphate and can be incorporated into the imagereceiving material as well as in the processing bath.

Sulphides of heavy metals such as antimony, bismuth, cadmium, cobalt, lead, nickel and silver; heavy metals such as silver, gold, platinum, palladium and mercury, preferably in their colloidal form, and/ or other substances which can serve as developing nuclei for the complexed silver halide are preferably incorporated into the imagereceiving layer. However, they can also be present in the processing bath. In the latter case, use is made of a lightsensitive and image-receiving material with a specific composition.

All the ingredients such as developing substances, complexing agents for silver halide, alkali, silver precipitating nuclei and the like which are necessary in a silver complex diffusion transfer process can be incorporated into the light-sensitive and/or image-receiving material used so that occasionally common water can be used as processing liquid.

In order to illustrate the effectiveness of the novel toning agents of the present invention, a photosensitive element comprising a paper support carrying a high speed large grain iodobromide emulsion (DXM 5665, E. I. du Pont de Nemours Company, Wilmington, Del.) at a coverage of about mgs. of silver per square foot was exposed and then brought into superposed relationship with a receiving element comprising cellulose diacetate having nickel sulfide disposed therein wherein the outer surface of the cellulose diacetate layer was hydrolyzed to regenerated cellulose; and a processing composition spread therebetween comprising:

Water cc 960 Potassium hydroxide g 480 Triethanol amine g 6 Uracil g 132 Zinc acetate g 16 Hydroxyethyl cellulose g 40 N,N-dimethoxyethyl hydroxylamine g 50 After a 30 second imbibition, the image-receiving element was separated.

A control film unit contained no toner for comparison with film units processed with various toners disposed in the processing composition. The following table summarizes the results obtained.

TABLE I Positive image M Silver image im. Dmintone Control 2. 70 0. 14 Brown. Compound 2 (1 mg./l0 cc. of developer) 2. 68 0. 07 Blue-black. Compound (1 mg./10 cc. of developer) 2. 4O 0. 18 Do.

What is claimed is: 1. The method which comprises contacting a silver image with a toner represented by the formula:

wherein Z is a fused alicyclic or heterocyclic ring system; R is selected from the group consisting of hydrogen and an atom of the ring system represented by Z.

2. The method as defined in claim 1 wherein said ring system contains 3 to atoms and is disposed to the pyrimidyl group in the 4,6; 4,5; 4,5,6; 5,6 or 1,6 positions.

3. The method as defined in claim 1 wherein said silver image is a positive silver image.

4. The method as defined in claim 3 wherein said silver image is formed by diffusion transfer.

5. The method as defined in claim 1 wherein said toner is 4,5-cyclopentahexahydropyrimidine-Z-thione.

6. The method as defined in claim 1 wherein said compound is imidazo[1,5-c] tetrahydropyrimidine 2- thione.

7. The method as defined in claim 1 wherein said compound is 4,6-trimethylene-hexahydropyrimidine-Z-thione.

8. A film comprising a photosensitive silver halide emulsion layer and a layer adapted to receive a positive silver image by diffusion transfer wherein said film unit includes as a toner, a polycyclic, S-substituted pyrimidine compound of the formula:

wherein Z is a fused alicyclic or heterocyclic ring system; R is selected from the group consisting of hydrogen and an atom of the ring system represented by Z.

9. The product as defined in claim 8 wherein said ring system contains 3 to 10 atoms and is disposed to the pyrimidyl group in the 4,6; 4,5; 4,5,6; 5,6 or 1,6 positions.

10. The product as defined in claim 8 wherein said layer adapted to receive a positive layer image includes silver precipitating nuclei.

11. The product as defined in claim 10 wherein a transparent support carries said layer adapted to receive a positive silver image.

12. The product as defined in claim 11 wherein said toner is associated with said layer adapted to receive a positive silver image.

13. The product as defined in claim 8 wherein said toner is associated with said silver halide emulsion layer.

14. A novel composition comprising a silver halide developing agent and a polycyclic, S-substituted pyrimidine compound represented by the formula:

wherein Z is a fused alicyclic or heterocyclic ring systern; R is selected from the group consisting of hydrogen and an atom of the ring system represented by Z.

15. The composition as defined in claim 14 wherein said composition is an aqueous alkaline composition.

16. The composition as defined in claim 14 which includes a silver solvent.

17. The composition as defined in claim 14 wherein said silver halide developing agent is hydroxylamine.

18. The composition as defined in claim 16 wherein said silver solvent is uracil.

References Cited UNITED STATES PATENTS 3,561,959 2/1971 Willems 9629 2,573,027 10/1951 Kendall et a1. 96-52 NORMAN G. TORCHIN, Primary Examiner J. L. GOODROW, Assistant Examiner U.S. Cl. X.R. 9652 

